device for mechanically drawing and releasing plastic containers

ABSTRACT

The invention falls in the field for transferring empty/full plastic containers provided with a collar or neck ring and, more particularly, it refers to a lever-shaped drawing device acting between the neck ring and the closing thread of the container. Said lever is kept pressed against a sliding channel ( 3 ) of the suspended bottles ( 2 ) and can retract for not interfering with said area when bottles build up. A substantially semicircular recess ( 9 ) partially surrounds the bottle neck where it interferes with the latter. Two levers are overlapped and by two springs (M 1, M 2 ) having different rigidities, two working conditions are defined: a first drawing condition and a second building-up condition; said springs allow the lever to draw also heavy containers and at the same time to disengage from the same if, along the path, there are other building up containers.

FIELD OF THE INVENTION

It is an object of the present invention a device for mechanicallydrawing, in a suspended condition, plastic containers provided with acollar and, particularly, the invention relates to a device for drawingeach bottle, shaped as a lever and acting between the collar ring andthe closing thread of the container, by a substantially semicircularrecess partially surrounding the bottle neck in the interference areawith the same. The lever is kept pressed toward a sliding channel of thesuspended bottles and can retract for not interfering with said areawhen bottles build up.

In the following description, reference will be made to bottle-likeplastic containers, but the invention can also be used for transportingpreforms or any plastic containers provided with a collar, called, by aperson skilled in the art, neck ring.

STATE OF THE ART

In bottling plants processing plastic bottles, there are two transporterfor transporting empty bottles across the plant, a mechanicaltransporter and a pneumatic one.

The pneumatic transporter has the disadvantage of handling hugequantities of air and therefore it fouls the containers. Moreover, it isnoisy and necessitates a high installed power with a consequent highenergy consumption. In addition, the pneumatic transport is not adaptedto transport small containers, such as the preforms.

The present invention refers to a mechanical-type transport.

The same applicant is also the holder of a similar application regardinga mechanical device for drawing empty plastic containers provided with acollar, in a suspended condition, wherein it is provided a powered chainlocated alongside of and parallel to the conveying channel; a pluralityof plates uniformly distributed and integral to the chain; a pluralityof shaped levers hinged to each corresponding plate and adapted tointerfere with the conveying channel by a spring element capable ofmaintaining each lever pressed against the conveying channel.

In an operative condition, the recess of the lever, by the action of thespring, engages the container and draws it by the chain; in case ofbuilding up bottles along the sliding channel, the drawing device isdislodged by the bottles piling up outside the channel area, this actiondisengages the container and stops the drawing step.

The disadvantages of the above device comprise the impossibility ofoptimally operating under both the conditions with a single spring as itis known hitherto, because during the drawing step, a too rigid spring,which would allow to draw also full and heavy bottles, is an hindrancewhen there is a bottles building-up: the lever aims to exert a force onthe building-up by causing shocks against the other bottles due to thepressure of the rigid spring; on the contrary, a yielding spring wouldallow an optimal disengagement but would be not capable of drawing fulland heavy bottles/containers, particularly along uphill advancinglengths.

DISCLOSURE AND ADVANTAGES OF THE INVENTION

The object of the invention consists of providing an improved mechanicaldevice for drawing plastic containers provided with a collar and in asuspended condition, which overcomes the abovementioned disadvantages.The device must operate in both the drawing and releasing steps during apossible building-up in the drawing channel.

Particularly, the new device comprises two springs having differentrigidities and acting on different components belonging to the deviceand more precisely the first one acts on the end part of the recess andthe other one acts on the initial part (at the hinge point); said twosprings, arranged in this way, allow the device to conveniently operateunder both the conditions, that is, for drawing heavy containers and atthe same time for easily disengaging from the same when there arebuilding up containers along the path.

Said objects and advantages are fulfilled by the drawing device, objectof the present invention, that is characterized for what is cited in thefollowing claims.

BRIEF DESCRIPTION OF THE INVENTION

These and other characteristics will be better pointed out by thefollowing description of some of its illustrated embodiments, as a nonlimitative example in the attached drawings.

FIG. 1 shows the device in a drawing condition,

FIG. 2 shows the device in an building-up condition.

DESCRIPTION OF THE INVENTION

For the features of the invention described in the following, itsapplication will be advantageous both to empty and fullcontainers/bottles.

Referring particularly to FIGS. 1 and 2, 1 generally shows a device formechanically drawing plastic containers 2 and/or preforms, of the typeprovided with a collar in a suspended condition.

The figures show two plan views and the containers 2 are carried along aconveying guide or channel 3 (a schematic channel or guide) and aresuspended by their neck; the cross size of the channel 3 is adapted toallow the container neck, and not the neck ring 2A or collar of thesame, to pass through.

Drawing means, such as a chain 6, slide parallelly to the guides, (thechain is driven by driving and operating means, not shown).

A plurality of plates 7, of which only one is shown, are fixed to saidchain 6, to which is connected the inventive drawing device hinged at apivoting point P1 on the same plate 7.

More particularly, device 1 comprises two levers and 5 overlapped andhinged to said pivoting point P1; levers 4 and 5 have different lengths,but one, lever 4 in the shown example, is shorter than the other.

Levers 4 and 5 have the same shape, that is, when they are overlappedthey have a single outline, as shown in FIG. 2; the only perceivabledifference is that lever 5 longitudinally projects and for said lengthit is possible to observe the presence of a gripping finger 8 movablewith respect to said lever 5 because it is pivoted to a hinge pointshown at P2.

Said hinge point P2 is located on the chain side, while on the otherside, finger 8 has a recess 9 having a substantially semicircularoutline 9A and shaped in order to partially surround the neck 2 of thebottle on the collar or neck ring 2A, in the interference area with thesame and to draw the bottle along the channel 3 when are complied theoperative conditions described in the following.

The shortest lever 4 has, on the portion of its outer end, in otherwords, between the pivoting point P1 and the outline semicircular edge4A, a hooking point (in the specific example a pawl 10 projecting fromthe plane) for the end of a first spring M1 connecting said pawl 10 to acorresponding fixed point 21 on the plate 7.

Said spring M1 is a traction spring, that is, it withdraws the hookingpoint 10 to the chain 6 taking it, without obstacles such as otherbottles in the channel 3, to a predetermined angular position (theposition shown in FIG. 1) corresponding to the position of the minimumenergy of the spring M1 itself; in said position, the lever 4, and alsolever 5, occupy the space defined by the channel 3, obviously they donot interfere with it but they stay above it.

Lever 4 is more slanted than lever 5 and this occurs due to two guideswith slots 4B and 5B arranged as a circumference arc and overlapped, theslots receiving a pin P3 fixed to the plate 7; slot 4B of the lever 4covers a longer angular length which causes the greater angling due tothe tension of spring M1. The purpose of pin P3, together with a stop 14advantageously located on lever 4, and the presence of springs M1 andM2, allows the device to efficiently operates both during the drawingand building-up steps, as described below.

As said, device 1 comprises a further spring M2 having a rigiditygreater than the above described spring M1.

Spring M2 operates inside the device, that is, connects lever 5 tofinger 8 by two stop points indicated at 11 and 12 in the figures: pin11 projects from lever 4 and exit trough a slit or slot 4C of the lever4, while the pin 12 projects from finger 8.

The function of the spring M2 consists of returning the finger 3 towardsthe channel 3, by forming a moment R3 opposite to the one necessary forreleasing the finger 8 from the bottle neck (said moment is indicated atR1 in the figure).

The stop 14 is registered and blocked on the lever 4 in order topositions, when spring M1 has the minimum energy, that is, when, asshown in FIG. 1, the channel is empty and spring M1 is uncompressed,between the pin P3 and pin 11 described before.

During the drawing step with a bottle or preform hooked in the recess 9of finger 8, the system acts as a rigid body, and spring M2 having agreater rigidity, advantageously keeps finger 8 attached thecontainer/bottle or preform; it follows that by locating a spring havinga suitable rigidity, it is possible to draw also high loads, withoutrunning the risk of losing them during the travel.

When a build-up of bottles forms in the channel 3, it is convenient tohave a fast removal of the device, and in this case spring M1, lessrigid than spring M2, starts to operate.

When lever 4 meets a building-up bottle/container (or preform), iteasily rotates around the pivot P1 due to the smaller rigidity of thespring M1, according to the rotation direction R3 and it locates itsside 4D parallelly to channel 3; during said rotation, the stop 14disengages from pins P3 and 11, releasing the previously formedengagement and allowing the disengagement of the hooking finger from theassociated bottle. In other words, lever 4 acts to block the lever 5 andfinger 8, by preventing the disengagement also under high loads.

By the present invention, both empty and full containers (anyway heavy)can be transported, without preventing their optimal releasing duringthe building-up step.

1. Device (1) for mechanically drawing and releasing plastic containers(2), either empty or filled, and/or preforms; said containers (2) orpreforms of the type comprising a collar (2A) adapted to rest on aconveying channel (3); a powered chain (6) arranged alongside andparallelly to the conveying channel (3) draws said device (1) which ishingedly supported at a pivoting point (P1) to a plate (7) integral withthe chain (6), a recess (9) being shaped such as to partially surroundthe bottle neck (2) above the collar or neck ring (2A), in theinterference area therewith and draw the latter along the channel (3)characterized in that it comprises a. two levers (4) and (5) beingoverlapped and hinged at said hinge point (P1), lever (5) being longerthan lever (4) and along said length a gripping finger (8) is pivoted tosaid lever (5) at a hinge point (P2); b. two springs (M1) and (M2)having different rigidities from each other, the spring (M2) being morerigid than the spring (M1); spring (M1) being suitable to carry, underminimum energy conditions, the lever (4) proximate to the space definedby the channel (3); the spring (M2) operating within the device (1),connects the lever (5) to the finger (8) by means of two correspondingstop points (11, 12), c. a stop (14) which is registered with and lockedto the lever (4) such as to be inserted, under minimum energy conditionsof the spring (M1), between a fixed pin (P3) on the plate (7) and thestop point (11) of the lever (5); said fixed pin (P3) passing throughcorresponding slots (4B) and (5B) which are semicircularly arranged onthe levers (4, 5), during the drawing step with the container (2) beingcoupled to the recess (9) of finger (8), the device operates as a rigidbody by means of the action of the stop (14) which is in the lockingposition; when the lever (4) meet a row of building up containers alongthe channel (3), it releases the stop (14) by overcoming the action ofthe spring (M1), and positions its flank (4D) parallelly to the channel(3), and the lever (5) and finger (8) can release the container (2)being drawn.
 2. Drawing device (1) according to claim 1, characterizedin that said levers (4) and (5) have the same shape in an overlappedconfiguration, except for the portion longitudinally projecting fromlever (5) on which the finger (8) is pivoted.
 3. Drawing device (1)according to claim 1, characterized in that said levers (4) and (5) eachcomprise a slot (4B) and (5B); said slots being semicircularly arrangedand overlapped, and receiving the fixed pin (P3) on the plate (7); theslot (4B) of lever (4) covers a greater angular length, therebyresulting in the greater angling caused by the tension of spring (M1).4. Drawing device (1) according to claim 1, characterized in that saidspring (M1) connects the lever (4) to the plate (7) by being hooked to apawl (10) and a corresponding fixed point (21) on the plate (7); saidpawl (10) being located between the pivoting point (P1) and thesemicircular edge (4A) of the lever (4).
 5. Conveyor system forcontainers of the type comprising a plurality of mechanical drawingdevices (1) according to claim 1.